Re: [PATCH 04/10] ARM: dts: rockchip: add startup delay to rk3288-veyron panel-regulators
From: Heiko Stübner <heiko@sntech.de>
Date: 2019-06-20 12:28:24
Also in:
linux-rockchip, lkml
Hi Doug, Am Donnerstag, 20. Juni 2019, 03:27:55 CEST schrieb Doug Anderson:
On Wed, Fri, 18 Mar 2016 Heiko Stuebner [off-list ref] wrote:quoted
The panels need a bit of time to actually turn on. If this isn't observed, this results in problems when trying talk to the panels and thus produces detection errors. 100ms seem to be a safe value for the time being. Signed-off-by: Heiko Stuebner <heiko@sntech.de> --- arch/arm/boot/dts/rk3288-veyron-jaq.dts | 1 + arch/arm/boot/dts/rk3288-veyron-jerry.dts | 1 + arch/arm/boot/dts/rk3288-veyron-minnie.dts | 1 + arch/arm/boot/dts/rk3288-veyron-speedy.dts | 1 + 4 files changed, 4 insertions(+)I know it was 3 years ago, but any idea how to reproduce the problems you were seeing without this patch? I believe the downstream kernel never had any delay like this and I'm not aware of any issues. I wonder if the need for this extra 100 ms delay is no longer there now that we have: 3157694d8c7f pwm-backlight: Add support for PWM delays proprieties. 5fb5caee92ba pwm-backlight: Enable/disable the PWM before/after LCD enable toggle. 6d5922dd0d60 ARM: dts: rockchip: set PWM delay backlight settings for Veyron
I just did a non-scientific test on my jerry+minnie and yes, simply reverting that patch does not seem to affect display bringup and I still get a prompt. So I guess we could just revert that patch in light of the changes. [patches welcome ;-) ] Heiko _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel